In general, collision absorption members for a vehicle are to absorb impacts from collisions with external objects and reduce pedestrian injuries during collisions with pedestrians, and representatively include bumpers provided at the front and rear of the vehicle.
The vehicle bumpers are configured of bumper covers and bumper back beams. Specifically, the bumper covers are mounted to the foremost and rearmost sides of the vehicle to define external appearances of the front and the rear thereof, and first undergo impacts transferred to the outside during collisions. The bumper covers are each provided with a buffer material therein in order to more easily absorb impacts transferred from the outside.
Meanwhile, each of the bumper back beams is located inside the associated bumper cover to absorb impacts transferred through the bumper cover, thereby serving to prevent damages of main parts such as a transmission and further to prevent injuries of occupants in the vehicle.
The bumper back beam is largely made of a steel material or a Glass Mat Thermoplastic (GMT) material.
In particular, the steel material has a relatively high strain and a heavy weight. For this reason, following a recent trend of vehicle lightening, a study on manufacturing of the bumper using a light material is actively ongoing. In this process, a light aluminum alloy tends to be actively applied to the vehicle.
Conventionally, a reinforcing phase such as a metal compound or carbon nanotube (CNT) is formed as a powder in order to improve elasticity of an aluminum alloy, but there is a limit in terms of cost competitiveness.
In addition, loss, wetting, and dispersion in molten aluminum may be caused when the reinforcing phase in the powdered form is inserted in a casting process. When only the reinforcing phase is added without an improvement of a base alloy, a cost increase and a difficulty of process control may be caused due to an increased amount of addition of the reinforcing phase for obtaining intended elasticity.
Thus, it is necessary to maximize generation of a boron compound playing a very important role in improvement of elasticity and to uniformly disperse the boron compound, generated by a spontaneous reaction, within the molten aluminum.
In the related art, a Korean conventional art entitled “An aluminum casting material including titanium boride and a method of producing the same” specifically discloses an aluminum alloy which has high elasticity compared to a conventional aluminum alloy without use of an expensive material such as carbon nanotube (CNT), and is applicable to all of general casting processes including high-pressure casting.
However, the above patent document does not resolve the problems such as loss, wetting, and dispersion in the molten aluminum during insertion of the reinforcing material in the powdered form, and the cost increase and the difficulty of process control due to the increased amount of addition of the reinforcing material.
The matters described as the related art have been provided only for assisting the understanding for the background of the present inventive concept and should not be considered as corresponding to the related art already known to those skilled in the art.